Weight-loss jabs and those for diabetes may be linked to a lower risk of dementia, a study suggests.
Semaglutide in particular, whose brand names include Wegovy and Ozempic, showed promise in cutting the risk of conditions that impair memory and thought processes, according to researchers.
Experts called for further research to shed light on how these drugs affect the brain and why they “may be offering a protective effect”.
Academics in the US analysed data from type 2 diabetes patients who were either taking GLP-1 receptor agonists (GLP-1RAs), which work by reducing food cravings, or sodium-glucose cotransporter-2 inhibitors (SGLT-2i) which work by reducing the amount of glucose the kidneys re-absorb allowing it to pass out of the body in urine.
GLP-1RAs is a class of medication that includes semaglutide, whose brand names include the jabs Wegovy and Ozempic, as well as Rybelus, which is taken as a tablet.
Wegovy was approved to tackle weight loss on the NHS in 2023, while Ozempic and Rybelus are available on the health service as treatments for type 2 diabetes.
The study included the health records of 396,963 people from the OneFlorida+ Clinical Research Consortium from January 2014 to June 2023.
All were aged over 50 with type 2 diabetes and no diagnosis of Alzheimer disease and related dementias (ADRD).
Researchers compared those on GLP-1RAs, SGLT-2i and other, second-line glucose-lowering drugs.
The analysis found that “both GLP-1RAs and SGLT2is were statistically significantly associated with decreased risk of ADRD compared with other GLDs, and no difference was observed between both drugs”.
Meanwhile, it was found that among the GLP-1RAs, “semaglutide seems to be promising in reducing the risk of ADRD”.
“This finding is particularly intriguing given the existing research on semaglutide’s neuroprotective properties,” researchers added.
Responding to the study, Dr Leah Mursaleen, head of clinical research at Alzheimer’s Research UK, said: “The results from this study support the growing evidence that GLP-1RA and SGLT-2 inhibitors medicines may reduce dementia risk.
“We don’t know yet why these medicines may be offering a protective effect, and will need more research to understand how they are affecting the brain.”
She added that while the findings are “interesting”, it is important to consider if other factors might be influencing results like overall health, income or education.
It comes as researchers in Ireland suggested GLP-1RAs are “associated with a statistically significant reduction in dementia”.
The study analysed 26 clinical trials involving almost 165,000 patients to determine if drugs like SGLT2is and GLP-1RAs, as well as diabetes medications metformin and pioglitazone, led to a reduction in risk of dementia or cognitive impairment.
It found most drugs “were not associated with an overall reduction in all-cause dementia” although “GLP-1RAs was associated with a statistically significant reduction in all-cause dementia”.
Both studies have been published in the journal Jama Neurology.
Dr Richard Oakley, director of research and innovation at Alzheimer’s Society, said: “Whilst both of these studies found a link between GLP-1RAs and reduced dementia risk, only one found SGLT2is, another class of diabetes drug, were also associated with a reduced risk.
“More research is needed to properly understand how diabetes treatments may lower the risk of dementia, by tracking people for longer, especially as they get older.”
Prof Tara Spires-Jones, director of the Centre for Discovery Brain Sciences at the University of Edinburgh, group leader in the UK Dementia Research Institute, and president of the British Neuroscience Association, said the data is “encouraging” for the “potential of using GLP-1Ras to lower dementia risk in people with diabetes”
“But even within these two strong studies, there are slightly conflicting results over SGLT2is highlighting the need for further research,” she added.
“It is important to note that these drugs do have side effects and that they are not guaranteed to prevent dementia.
“The studies had important limitations including a relatively short follow up time. Future work will be important to understand how risk factors like diabetes and obesity increase risk of dementia to develop effective treatments and prevention strategies.”
Masud Husain, a professor of neurology and cognitive neuroscience at the University of Oxford, added: “For me, these new retrospective analyses suggest that GLP-1 receptor agonists, particularly semaglutide, might reduce the risk of developing dementia in people with type 2 diabetes.
“But we need data from prospective trials to provide stronger evidence.
“The wider question of whether such drugs might also be protective against dementia in people who don’t have diabetes is a really intriguing one, and the focus of several ongoing clinical trials.”
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